Semantic Conventions for Connect RPC

Status: Experimental

The Semantic Conventions for Connect extend and override the RPC spans and RPC metrics Semantic Conventions that describe common RPC operations attributes in addition to the Semantic Conventions described on this page.

Connect RPC Attributes

rpc.system MUST be set to "connect_rpc".

Below is a table of attributes that SHOULD be included on client and server Connect RPC measurements.

Attribute	Type	Description	Examples	Requirement Level
rpc.connect_rpc.error_code	string	The error codes of the Connect request. Error codes are always string values.	cancelled	Conditionally Required: [1]
rpc.connect_rpc.request.metadata.<key>	string[]	Connect request metadata, <key> being the normalized Connect Metadata key (lowercase, with - characters replaced by _), the value being the metadata values. [2]	rpc.request.metadata.my_custom_metadata_attribute=["1.2.3.4", "1.2.3.5"]	Opt-In
rpc.connect_rpc.response.metadata.<key>	string[]	Connect response metadata, <key> being the normalized Connect Metadata key (lowercase, with - characters replaced by _), the value being the metadata values. [3]	rpc.response.metadata.my_custom_metadata_attribute=["attribute_value"]	Opt-In

[1]: If response is not successful and if error code available.

[2]: Instrumentations SHOULD require an explicit configuration of which metadata values are to be captured. Including all request metadata values can be a security risk - explicit configuration helps avoid leaking sensitive information.

[3]: Instrumentations SHOULD require an explicit configuration of which metadata values are to be captured. Including all response metadata values can be a security risk - explicit configuration helps avoid leaking sensitive information.

rpc.connect_rpc.error_code MUST be one of the following:

Value	Description
cancelled	cancelled
unknown	unknown
invalid_argument	invalid_argument
deadline_exceeded	deadline_exceeded
not_found	not_found
already_exists	already_exists
permission_denied	permission_denied
resource_exhausted	resource_exhausted
failed_precondition	failed_precondition
aborted	aborted
out_of_range	out_of_range
unimplemented	unimplemented
internal	internal
unavailable	unavailable
data_loss	data_loss
unauthenticated	unauthenticated

Connect RPC Status

If rpc.connect_rpc.error_code is set, Span Status MUST be set to Error and left unset in all other cases.